<?php

class phpthumb_ico {

    function __construct() {
        return true;
    }


    function GD2ICOstring(&$gd_image_array) {
        foreach ($gd_image_array as $key => $gd_image) {

            $ImageWidths[$key]  = ImageSX($gd_image);
            $ImageHeights[$key] = ImageSY($gd_image);
            $bpp[$key]          = ImageIsTrueColor($gd_image) ? 32 : 24;
            $totalcolors[$key]  = ImageColorsTotal($gd_image);

            $icXOR[$key] = '';
            for ($y = $ImageHeights[$key] - 1; $y >= 0; $y--) {
                for ($x = 0; $x < $ImageWidths[$key]; $x++) {
                    $argb = $this->GetPixelColor($gd_image, $x, $y);
                    $a = round(255 * ((127 - $argb['alpha']) / 127));
                    $r = $argb['red'];
                    $g = $argb['green'];
                    $b = $argb['blue'];

                    if ($bpp[$key] == 32) {
                        $icXOR[$key] .= chr($b).chr($g).chr($r).chr($a);
                    } elseif ($bpp[$key] == 24) {
                        $icXOR[$key] .= chr($b).chr($g).chr($r);
                    }

                    if ($a < 128) {
                        @$icANDmask[$key][$y] .= '1';
                    } else {
                        @$icANDmask[$key][$y] .= '0';
                    }
                }
                // mask bits are 32-bit aligned per scanline
                while (strlen($icANDmask[$key][$y]) % 32) {
                    $icANDmask[$key][$y] .= '0';
                }
            }
            $icAND[$key] = '';
            foreach ($icANDmask[$key] as $y => $scanlinemaskbits) {
                for ($i = 0; $i < strlen($scanlinemaskbits); $i += 8) {
                    $icAND[$key] .= chr(bindec(str_pad(substr($scanlinemaskbits, $i, 8), 8, '0', STR_PAD_LEFT)));
                }
            }

        }

        foreach ($gd_image_array as $key => $gd_image) {
            $biSizeImage = $ImageWidths[$key] * $ImageHeights[$key] * ($bpp[$key] / 8);

            // BITMAPINFOHEADER - 40 bytes
            $BitmapInfoHeader[$key]  = '';
            $BitmapInfoHeader[$key] .= "\x28\x00\x00\x00";                              // DWORD  biSize;
            $BitmapInfoHeader[$key] .= $this->LittleEndian2String($ImageWidths[$key], 4);      // LONG   biWidth;
            // The biHeight member specifies the combined
            // height of the XOR and AND masks.
            $BitmapInfoHeader[$key] .= $this->LittleEndian2String($ImageHeights[$key] * 2, 4); // LONG   biHeight;
            $BitmapInfoHeader[$key] .= "\x01\x00";                                      // WORD   biPlanes;
            $BitmapInfoHeader[$key] .= chr($bpp[$key])."\x00";                          // wBitCount;
            $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00";                              // DWORD  biCompression;
            $BitmapInfoHeader[$key] .= $this->LittleEndian2String($biSizeImage, 4);            // DWORD  biSizeImage;
            $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00";                              // LONG   biXPelsPerMeter;
            $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00";                              // LONG   biYPelsPerMeter;
            $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00";                              // DWORD  biClrUsed;
            $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00";                              // DWORD  biClrImportant;
        }


        $icondata  = "\x00\x00";                                      // idReserved;   // Reserved (must be 0)
        $icondata .= "\x01\x00";                                      // idType;       // Resource Type (1 for icons)
        $icondata .= $this->LittleEndian2String(count($gd_image_array), 2);  // idCount;      // How many images?

        $dwImageOffset = 6 + (count($gd_image_array) * 16);
        foreach ($gd_image_array as $key => $gd_image) {
            // ICONDIRENTRY   idEntries[1]; // An entry for each image (idCount of 'em)

            $icondata .= chr($ImageWidths[$key]);                     // bWidth;          // Width, in pixels, of the image
            $icondata .= chr($ImageHeights[$key]);                    // bHeight;         // Height, in pixels, of the image
            $icondata .= chr($totalcolors[$key]);                     // bColorCount;     // Number of colors in image (0 if >=8bpp)
            $icondata .= "\x00";                                      // bReserved;       // Reserved ( must be 0)

            $icondata .= "\x01\x00";                                  // wPlanes;         // Color Planes
            $icondata .= chr($bpp[$key])."\x00";                      // wBitCount;       // Bits per pixel

            $dwBytesInRes = 40 + strlen($icXOR[$key]) + strlen($icAND[$key]);
            $icondata .= $this->LittleEndian2String($dwBytesInRes, 4);       // dwBytesInRes;    // How many bytes in this resource?

            $icondata .= $this->LittleEndian2String($dwImageOffset, 4);      // dwImageOffset;   // Where in the file is this image?
            $dwImageOffset += strlen($BitmapInfoHeader[$key]);
            $dwImageOffset += strlen($icXOR[$key]);
            $dwImageOffset += strlen($icAND[$key]);
        }

        foreach ($gd_image_array as $key => $gd_image) {
            $icondata .= $BitmapInfoHeader[$key];
            $icondata .= $icXOR[$key];
            $icondata .= $icAND[$key];
        }

        return $icondata;
    }

    function LittleEndian2String($number, $minbytes=1) {
        $intstring = '';
        while ($number > 0) {
            $intstring = $intstring.chr($number & 255);
            $number >>= 8;
        }
        return str_pad($intstring, $minbytes, "\x00", STR_PAD_RIGHT);
    }

    function GetPixelColor(&$img, $x, $y) {
        if (!is_resource($img)) {
            return false;
        }
        return @ImageColorsForIndex($img, @ImageColorAt($img, $x, $y));
    }

}

?>